Office telephone system



Aug. 28, 1928. 1,682,159

B. D. WILLIS IUL'I'I-OFPICE' TELEPHONE SYSTEM Filed y 2 1925 2 Sheets-Sheet 1 R f'zuan ar- Barnard' .U. M21115 Aug. 28, 192& 1,682,159

B. D. WILLIS HULTI- OFFICE TELEPHONE SYSTEM Filed July 24, 1925 2 Shpet-Sheet 2 -Inuerz Bernard Dlizllzs l tatented I UNITED STATES PATENT OFFICE.

BERNARID D. WILLIS, OF OAK PARK, ILLINOIS, ASSIGNOR, BY MESNIEl ASSIGNMENTS,

TO AUTOMATIC ELECTRIC ENG, OF CHICAGO, ILLINOIS, A CORPORATION OF DELA- WARE.

MULTIOFFICE TELEPHONE SYSTEM. vi

Application filed July 24, 1925. Serial No. 45,731.

The present invent-ion relates to multioilice telephone systems in general, but is concerned more particularly with the provision of anew and improved arrangement for handling pay-station calls in automatic telephone systems through a manual switchboard located in a remote office of the same multi-oflice net work.

The invention is shown applied to a multiofiice telephone system in which the ordinary subscriber-to-subscriber calls are on a fiat rate basis and are set up by the subscribers themselves entirely without the aid of an operator, and in which the calls from public telephones, located in drug stores, hotels, and the like. are charged for individually and are handled through the medium of a manual. switchboard by an operator wao receives the desired number from the calling subscriber and sets up the connection through the regular automatic switches. Probably the simplest way to handle the above situation is to place'an operator in each oflice to receive the incoming pay-station calls and to complete them and see that the proper coin is deposited. This however is undesirable in case certain of the oiliees terminate only a small number of pay station lines. or are small outlying oflices. or for any similar reason do not justify the provision of an opera.- tor at all times to take care of the pay station service.

Accordingly the manual. switchboards for handling the pay station calls are placed in one or more of the more nearly centrallylocated automatic oiiices, and the pay-station calls from any one of the other offices are first trunked in to a manual switchboard in the nearest oflice provided with an operator from which point they may be extended as the operator sees fit.

When the above arrangement is provided, the situation is met with wherein a subscriber local. to a particular oiiice makes a call (which is first trunlred to a switchboard in a remote oi'lice) intended for a subscriber located in thesame local office. In this case, unless special provisions are made, two 1' nterofiice trunk lines are tied up on a purely local call. This may have several ill effects. One effect is the unwarranted expense of providing sufiicient trunk lines to allow two to be taken up for each local call, and. another effect is the unnecessary transmission loss on local calls which occurs in case the trunk lines connecting the originating otiiee with the remote ofiice are of the non-loaded-cable type and of some considerable length. Accordingly, arrangements are provided so that, when a call originated by a pay-station subscriber is for a subscriber local to his own ofiice, the operator may dial back over the same line through which the connection was extended to her position and operate automatic switches in the local office to complete the connection locally. I

Another object of the invention is to en able the operator to free the inter-o'l'lice trunk line as soon as she sets up a local connection originated in a distant ofiice.

Another object of the invention is to provide arrangements whereby, when the operator sets up a connection in the office local to the calling subscriber, the calling and called lines are not telephonically connected together until the operator is assured that the calling subscriber has deposited the proper coin together with provisions whereby the operator may converse with either of the two subscribers separately before their lines'are telephonically connected together.

The other objects and features of the invention relate for the most part to the circuit details involved in carrying out the foregoing.

Referring now to the drawings comprising Figs. 1 and 2, they show by means of the usual circuit diagrams a sufficient amount of apparatus in a telephone system embodying the principles of the invention to enable the inventionto be. understood.

Fig. 1 shows a common battery pay station A and the associatedline which terminates at the automatic exchange in the line switch LS, which in common with the other line switches associated with pay-station lines,

has access to a number of first selectors of which thefirst selector S is one. The trunk circuit TC is inserted in the trunk line'between the line switch banks and the selector S in order to enable the operator to control the setting up of a connection and to supervise the deposit of the coin etc. This draw ing shows also the relays 64 and 65 for controlling the association of a control trunk with the trunk line extending to the selector S. It will be understood that the circuits of the selector S are well known and are for that reason not shown in full.

Fig. 2 shows the trunk line TL extending from the exchange in which the apparatus shown in Fig. 1 is located to a remote exchange provided with a manual switchboard for the handling of pay-station calls. This trunk line terminates at the automatic exchange in the terminals 121123 and is connected as shown through the medium of the jumpers 118-12O to the finder switch F which has access to the trunk circuit TC.

The trunk line TL terminates at the remote end in the jack J with which the trunk circuit TC is associated.

Regarding the automatic switches shown, the line switch L8 is, mechanically, of the well known rotary type having wipers which are advanced in one direction only and which are advanced upon the restoring stroke of the associated stepping magnet. The finder F, Fig. 2, is similar, mechanically, to the line switch LS. v

The selector 5, Fig. 1, is assumed to be a vertical and rotary switch having bank contacts arranged in horizontal rows or levels and having a primary moven'ient in a vertical direction to select a desired level of contacts and an automatic rotary movement to select an idle trunk line in the selected level.

The invention having been described generally, a detailed description of the operation of the apparatus shown will now be given. For this purpose it will be assumed that the subscriber at substation A desires to converse with a subscriber whose line terminates in the same local office. Accord ingly the subscriber at substation A removes his receiver to make the call.

hen the receiver is removed at substation A, a circuit is closed over the line conductors 6 and 7 for line relay 10 of the line switch LS. Line relay 10 thereupon energizes and places ground on the private normal conductor 8 at armature 14, thereby making the calling line busy in the banks of the connector switches having access to it and closing a circuit through switching relay 9 and stepping magnet 16. At armature 15, relay 10 connects test wiper 18 to the junction of relay 9 and stepping magnet 16.

Assuming the trunk line upon which the wipers of the line circuit are standing is not busy, the operation of relay 10 at armature 15 does not have any particular function at this time, and switohin g relay 9 energizes right away. seizing the trunk. Assuming. however, that the trunk line is busy, switching relay 9 is short circuited by the ground potential encountered on the busy test contact by test wiper 18 and does not energize. In this case the self-interrupting stepping magnet 16 is operated from the ground potential encountered on the busy test contact and it operates in a buzzer like manner to advance the wipers 17-19 step by step in search of an idle trunk line.

lVhen an idle trunk line is reached, for example the one comprising conductors 20 22, the operation of stepping magnet 16 ceases owing to the absence of ground potential on the associated test contact. Also, relay 9, being no longer short circuited, energizes in series with stepping magnet 16, which magnet however is not able to operate at thistime owing to the relatively high resistance of relay 9. Upon energizing, relay 9 opens the test circuit and prepares the holding circuit at armature 12, at the same time placing ground on test wiper 18 through the working contact and armature 1 1, thereby making seized trunk busy; and at armatures l1 and 13 it disconnects the line conductors 6 and 7 from the winding of line relay 10 and ground respectively and extends them by way of wipers 17 and 19, conductors 20 and 22, normally closed contacts controlled by armatures 38 and 42, conductors 18 and 50, and the contacts of relay 85 to line relay 81 of the selector S. Line relay 81 now energizes over the calling line and closes at armature 88 a circuit for the slow acting release relay 82, which thereupon energizes and prepares the switch for operation, which consists among other things in placing ground on the release trunk conductor 4C9 at armature 84, thereby extending ground through conductor 21, wiper 18, and armature 12 and its working contact to switching relay 9 of the line switch LS to maintain this relay operated. This operation is completed. it will be understood, before the slow acting relay 10 has had time to fall back.

As a further result of the placing of ground on the release trunk conductor 19, a

circuit is closed through the normally closed contacts controlled by armature 72 of relay 37 for relay 31, which relay accordingly energizes and at armature 38 places a local bridge across conductors 418 and 50 leading to selector S, at the same time disconnecting these conductors from the calling line. The local bridge across conductors 4i8-50 includes armatures 88 and 12, normally closed contacts controlled by armatures 4:4; and 17, upper and lower windings of the differentially wound relay 36, terminals and 58, jumpers and 5 11. and armature 69 and its resting contact of relay 65. Accordingly, line relay 81 ot the selector S is held up over this local bridge and the calling line has no further control over it for the time being. As a further result of the energization of relay 81 it extends the calling line to the windings of the double wound relay 32. Relay 32 is accordingly energized over the calling line and at armature 43 it completes a supervisory bridge through the impedance 33 across conductors7 3 and 74 for a purpose to be hereinafter explained.

As a further result or the placing of the relay 65.

Responsive to the grounding of the start conductor 70, as above explained, a circuit is closed through armature 115 of the switching relay 103 of the finder F and its resting contact for start relay 102. At armature 110, relay 102 closes a circuit through switching relay 103 and stepping magnet 101 in series, and at armature 111 it connects test wiper 105 to the junction of magnet 101 and relay 103. Accordingly, the finder F is advanced to find an ungrounded test contact under the control of test wiper 105 in the same manner as explained hereinbetere in connection with the line switch LS, Fig. 1.

When the terminals of the calling trunk circuit TC are found, switching relay 103 energizes in series with stepping magnet 101, and at armatures 112 and 117 extends the conductors 124 and 126 of the trunk line TL through wipers 104 and 108 to conductors 59 and 63 associated with the trunk circuit TC; opens the test circuit and grounds wiper 105 at armature 113; closes a locking circuit for itself at armature 114, which extends from the grounded release trunk conductor 49, Fig. 1, through armature 7 5 and its resting contact, terminal 47 jumper 53, conductor 61, contact in the bank of wiper 106 and said wiper, working contact and armature 114, of relay 1.03 and then to battery through magnet 101. At armature 115, relay 103 disconnects the start wire 70 from the slow acting start relay 102 and prepares to extend it through armature 109 and its resting contact to the outgoing start wire 170 when slow acting relay 102 falls back, as it does shortly.

Responsive to the above pointed out grounding of wiper 105 of the finder F at armature 113, a circuit is closed through conductor 62, and armature 66 and its working cont-act of relay 64 forthe cut-off relay 65. Relay 65 energizes over this circuit and removes ground from start conductor at armature 68, and at armature 69 opens the shunt across conductors 59 and 63 through which the line relay 81 of the selectors S has been energized subsequent to the operation of relay 31, above pointed out.

Line relay 81 of the selector S now remains energized over conductors 59 and 63 on account of the fact that these conductors are connected to a closed bridge on the di tant end of the trunk line TC through wipers 104 and 108 of the finders F, working contacts and armatures 112 and 117, jumpers 118 and 120, conductors124 and 126, contacts of the jack J, contacts of the key K, and relay 142. v

Relay 142 energizes in series with line relay 810i the selector S, Fig. 1, and closes at armature 145 a circuit for the line lamp 148.

When the operator notes the'lighted condition of the lamp 148, she throws the answering key K thereby connecting her common listening and calling device taps to conductors 146and'147 and disconnecting relay 142 from in bridge of theseconductors, and at the upper contact of the key K a circuit is closed for relay 141, which relay energizes and places ground on the upper and lower terminals of relay 142 at armatures 143 and 144 preparatory to the switchover operation when the key K is subsequently restored.

In order to converse with the calling subscriber, the operator throws her switching key K thereby placing battery on conductor 125, which is extended through the terminal 122, jumper 119, armature 116, and its working contact, wiper 107 and the bank contact on which it is standing, conductor 60, jumper 52, and terminal 56 to the switching relay 34 of the trunk circuit TG, to ground through working contact and armature 40. Switching relay 34 energizes and closes a local holding circuit at armatures 44 and 47 through the resistance 35 for line relay 81 of the selector S, at the same time opening an associated point in the talking circuit and at armatures 45 and 46 it completes a talking circuit from'thetrunk conductors 20 and 22 through the working contactsand armatures 39 and 41, the associated condensers, conductors 74 and 73, and armatures 45 and 46 to the talking conductors leading to the operators switchboard over the trunk line TL. Upon conversing with'the calling subscriber and learningthat he desires to converse with a subscriber local to his own exchange, the operator restores the key .K, thereby permitting the switching relay 34, Fig. 1, to fall back and restore the circuits to their condition existing immediately before its energization, after which the operator manipulates the calling device 150 in accordance with the digits in the desired number. I

The selector S is operated in the usual manner responsive to the first digit to raise its wipers 86, 87, and 88 opposite the desired level of bank contacts after which it auto-- maticallyrotates'the wipers 8688'into on gagement with the bank contacts of an idle trunk (for example bank contacts 8991), whereupon the switching relay 85 operates in the usual manner to extend the connection to the idle trunk.

The remaining part of the connection is set up in the well known manner.

hen the called subscriber responds, the operator converses with him to ascertain whether or not he is the desired subscriber, and, assuming that he is, she tells him that he is wanted in a connection, but to wait a moment, sitter which she throws her switching key K again to bring about the energization of relay 34, Fig. 1, which in the manner hereinbefore described switches her talking circuits from the direction of the selector S to the conductors and 22 to enable her to converse with the calling subscriber to the exclusion of the called subscriber.

The operator now tells the calling subscriber that his connection is ready and she tells him to deposit a coin of the desired denomination in the coin box indicated by the opening 2, the coin chute 3, and the vibratory spring 4. The subscriber now places the coin in the opening 2 whereupon it rolls down the chute 3 and strikes the spring 4 and then rolls down into the collecting chamber. The spring 4, upon being struck, emits a musical note which is transmitted over the calling line to the operator through the medium of the associated transmitter. Upon being thus informed that the calling subscriber has deposited the coin, the operator restores her switching key K allowing switching relay 34 of the trunk circuit TC to fall back, and she also restores her answering key K, bridging relay 142 across conductors 146 and 147 and opening the cir-v cuit of the slow acting relay 141. Since both terminals of relay 142 are grounded, the circuit through differential relay 36 is unbalanced to such an extent that it operates and at armature 71 closes a circuit for relay 37. Relay 37 thereupon energizes and at armature 72 locks itself to the release trunk conductor 49, at the same time disconnecting relay 31 from conductor 49. Relay 31 now deenergizes and connects the calling and called lines at the normally closed contacts controlled by arma-tures 38 and 42.

As a further result of the energization of relay 37, ground is removed from conductor 61 at arn'iature 75, whereupon relay 64 falls back and at armature 66 opens the circuit of relay 65. The switching relay 103 of the finder F, being unlocked, falls back. reverting the trunk line TL to common use.

hen the calling subscriber replaces his receiver, the ground potential is removed in the usual manner from the release trunk conductor of the established connection, whereuponrelay 85 of the selector S falls back, with the result that the switch is restored to normal in the usual manner and the switching relay 9 of the line switch LS is deenergized. The entire connection is now released and apparatus involved therein is ready to be used in establishing a subsequent connection.

Assume now that the subscriber at substation A desires to converse with a subscriber whose line terminates in the ,oiiice in which the operators switchboard shown in Fig. 2 is located. Upon removing the receiver a selector (for example the selector S) is seized, and a trunk line (for example the trunk line TL) is connected through the medium of the finder F to the trunk circuit TC. In this case after the operator has operated the keys K and K she converses with the calling subscriber and ascertains the destination of the call, she inserts the plug of a cord circuit (not shown) at her switchboard into the jack J. The insertion of the above mentioned plug into the jack J results in the extension of conductors 124 and 12-6 to the talking strands of the cord circuit and in conductors 124 and 126 being disconnected irom conductors 146 and 147, and it results also in the contacts of the key K being shunted at the upper contacts of the jack J so as to maintain the switching relay 34 of the trunk circuit TC operated. The operator now restores her key K, and she restores the key K .to free her head set from the trunk circuit TC. In this case there is no unbalancing ground potential placed on conductors 1 24 and 126 owing to the fact that the conductors 146 and 147 with which relay 142 is associated are both disconnected ;trom conductors 124 and 126 at the cut-off contacts of the jack J.

Since the switching relay 34 of the trunk circuit TC, Fig. 1. is operated, the conductors of the trunk line TL are extended through conductors 59 and 63, jumpers 51 and 54, terminals and 58, working contacts and armatures 45 and 46, and conductors 74 and 73 to the bridge includingthe impedance 33, which is closed at armature 43 of relay 32, which is now under the control of the calling line. Accordingly, the battery feed supervisory relay in the cord circuit used to extend the connection from the jack J, Fig. 2, is operated to extinguish the super visory lamp in the usual manner.

- The operator now extends the connection to the desired line in any well known or desired manner.

When the calling subscriber replaces his receiver upon the termination of the ensuing conversation, relay 32 of the trunk circuit TC, Fig. 1, falls back and opens, at armature 43, the supervisory bridge through the impedance 33, whereupon the battery feed su crvsory relay (not shown) in the cord. circuit associated. with the jack J, Fig. 2, falls back and permits the associated supervisory lamp to become lighted to give'the operator a disconnect signal.

Upon receiving the disconnect signal, the operator removes her plug from the jack J, whereupon the upper contact of the jack J removes battery through the resistance 127 from the switching conductor 125, permitting switching relay 34 of the trunk circuit- TO to fall back. Then this occurs the local holding circuit through resistance 35 for line relay 81 of the selector S is opened whereupon line relay 81 falls back and opens the circuit of the slow acting release relay 82 which relay deenergizes shortly thereafter and removes ground from release trunk con ductor 49 at armature 84. When this occurs, switching relay 9 of the line switch LS 'falls back and relay 31 of the trunk circuit TC deenergizes. As a further result of the removal of ground from the release trunk conductor 19, relays 64 and 65, Fig. 1, and relay 103 of the finder F, Fig. 2, all fall back.

The entire connection is now released and thial apparatus is ready to be used in another ca It will be understood of course that the situation set forth herein is subject to considerable modification. For example, calls from the ofiice in which the equipment shown in Fig. 1 is located to certain other ofiices near by may of course bemade through the selector S, instead of through the jack J. 'Also it is obvious that calls to any desired ofiice may be made through the medium of the ack J and the associated cord circuit as the occasion demands.

It will be evident that in some cases it may be that the number of trunk lines such as TL must be substantially equal to the number of trunk circuits such as TC in which case the saving due to the introduction of the finders, such as F, does not pay for the cost of the finders. In this-case the jumpers 51-54 are omitted, together with the jumpers 118-12O and the contacts 55, 56, and 58 are connected respectively to the contacts 123, 122, and 121, Fig. 2, by means of jumpers in the usual manner, and the finders, such as F, and the start and cut-ofl' relays, such as 6 1 and 65, are of course omitted. I

What is claimed is:

1. In a telephone system, an automatic switch, an operators switchboard, a calling line, means responsive to the removal of the receiver on the, calling line for extending a connection to said automatic switch and for extending another connection to said switchboard, and a sending device at the operators switchboard for setting up a connection including said automatic switch to a called line, said first named means including means for maintaining the calling line telephonically disconnected from said connection to said automatic switch, for ex-? tending another connection to said switchboard, and for telephonically disconnecting the line from the switch, a sending device at said switchboard for setting up a connection to a called line including said automatic switch, and operator controlled means for subsequently completing the telephonic connection between the calling and the called lines. v

3. Ina telephone systenna calling line, an automatic switch, an operators switchboard, means responsive to the removal. of the receiver on the calling line for extending a connection to said automatic switch and for extending another connection tosaid switchboard, a sending device at said switchboard for setting up a connection to a called line including said automatic switch, and operator controlled means for establishing a talking connection between the operators switchboard and either of the two of said lines independently.

1. In a telephone system, a calling line, an automatic-switch, an operators switchboard, means responsive to the removal of the receiver on the calling linefor extending a connection to said automatic switch, and for extending another connection to said switchboard, and for telephonically disconnecting the line from the switch, a sending device at said switchboard for setting up a connection toa called line including said automatic switch, and means auto matically responsive to the disconnection of the sending device for completing a telephonic connection between the two lines.

are a telephone system, an automatic switch, a first trunk line extending to said switch comprising two sections, means responsive to the removal of the receiver on a calling line for completing a connection from the calling line to said switch by way of both sections of said first trunk line in series, a manual switchboard, a second trunk line leading thereto, means responsive to the completion of said connection for separating the two sections of said first trunk line from each other and for connecting the section connected to the switch to the said second trunk line, and a signal at said switchboard operated responsivev to the last named operation. j

6. In a telephone system, an automatic switch, a first trunk line extending to said switch comprising two sections, means responsive to the removal of the receiver on from the calling line to said switch byway of both sections of said first trunk line in series, a manual switchboard, a second trunk line leading thereto, means responsive to the completion of said connection for separating the two sections of said first trunk line from each other and for connecting the section connected to the switch to the said trunk line leading to said switch board, and an operator-controlled calling device at said switchboard for controlling the setting up of a connection to a called line includingsaid switch.

7. In a telephone system, an automatic switch, a first trunk line extending to said switch comprising two sections, means re sponsive to the removal of the receiver on a calling line for completing a. connection from the calling line to said switch by way of both sections of said first trunk line in series, a manual switchboard, a second trunk line leading thereto, means responsive to the completion of said connection for separating the two sections of said trunk line from each other and for connecting the second section to the said second trunk line, operator controlled means for temporarily switching the second trunk line from the second section to the first section of the first trunk line, to enable the operator to converse with the calling subscriber, operator controlled means for setting up a connection including said automatic switch to a called line, and operator controlled means for rejoining said two trunk-line sections.

8. In a telephone system, an automatic switch, a first trunk line extending to said switch comprising two sections, means responsive to the removal of the receiver on a calling line for completing a connection from the calling line to said switch by way of both sections of said trunk line in series, a manual switchboard, a second trunk line leading thereto, means responsive to the completion of said connection for separating the two sections of said first trunk line from each other and for connecting the second section tosaid second trunk line, operator-controlled. means for temporarily switching the second trunk line from the second sect-ion to the first section of the first trunk line to enable the operator to converse with the calling subscriber, operator controlled means for setting up a connection including said automatic switch to a called line, said first named operator controlled means being again controllable by the operator to temporarily switch the second trunk line over to the first section of the first trunk line, and operator-controlled means for rejoining said two trunkline sections.

9. In a telephone system, an automatic switch, a first trunk line extending to said switch comprising two serially connected sections, means responsive to the removal of the receiver on a calling line for extend-' trunk line, operator controlled means for setting up a connection including said second section and said switch to a called line, and operator controlled means for subsequently completing a telephonic connection between said trunk-line sections.

10. In a telephone system, a line, means operated responsive to the initiation of a call to extend the line over two branches one of which terminates at an operators position and the other in an automatic switch, means at the operators position to further extend the line at will either over the auto,- matic switch branch or over the branch leading to the operators position, means for indicating to the operator that a coin has been deposited, and means at the operators position to control the establishment of a talking connection over the line. I

11. In an automatic telephone system, the combination with a manual pay station line, of means for extending the line over two branches, an operators position terminating one branch, an automatic switch terminating the other branch, mean at the operators position for extending the line over the automatic switch, means at the pay station for indicating to the operator that a coin has been deposited, and means at the operators position for controlling the establishment of a talking connection over the line.

12. In an automatic telephone system, in

combination, a pay station line, means operated responsive to the initiation of a call for extending the line to an automatic switch, means for extending a branch from the switch to an operators switch-board, means whereby the operator may further extend the line either over the automatic switch or by way of the switchboard, at will, and means for indicating to the operator that a coin has been deposited.

, 13. In an automatic telephone system, a pay station line, means operated responsive to the initiation of a call for extending the line to an automatic switch, means for extending a branch from the switch to an operators switchboard, means whereby the operator may control the establishment of a connection to a called line, and means for indicating to the operator that a coin has been deposited to pay for the connection.

14. In an automatic telephone system, a pay station line, means including a line switch operated responsive to the initiation of a call for extending the line to an automatic switch responsive to the operation of said line switch, means for extending a branch from the switch to an operators switchboard, means whereby the operator may operate the automatic switch to set up the desired connection, and means for indi; cating to the operator that a coin has been deposited.

15. In an automatic telephone system, a paystation line, means operated responsive to the initiation of a call for extending the line to an automatic switch, means for extending a branch from the switch to an operators switchboard, means whereby the operator may operate the automatic switch to establish a connection to a desired line, means whereby the operator may converse with the called or the calling party while preventing conversation between the parties, means for indicating to the operator that a coin has been deposited, and means under the control of the operator whereby the called and calling parties are connected.

In witness whereof, I hereunto subscribe my name this 21st day of July, A. D. 192 5.

BERNARD 'D. WILLIS. 

